Importance of isothermal mixing processes to the understanding of lift-off and blowout of turbulent jet diffusion flames

1989 ◽  
Vol 76 (2) ◽  
pp. 197-212 ◽  
Author(s):  
William M. Pitts
Keyword(s):  
Diffusion Flames ◽  
Turbulent Jet ◽  
Mixing Processes ◽  
Jet Diffusion Flames ◽  
Lift Off ◽  
Isothermal Mixing

Transport in Turbulent Jet Diffusion Flames With Annular Counterflow

2001 ◽  
Author(s):  
Shuichi Torii ◽  
Sze Man Simon Chan ◽  
Toshiaki Yano
Keyword(s):  
Diffusion Flames ◽  
Volume Flow Rate ◽  
Outer Cylinder ◽  
Turbulent Jet ◽  
Turbulent Shear ◽  
Shear Effect ◽  
Fuel Gas ◽  
Jet Diffusion Flames ◽  
Experimental Apparatus ◽  
Lift Off

Abstract The present study deals with the augmentation of the turbulent shear effect on transport in turbulent jet diffusion flames due to the presence of air-suction flow and the possibility of extending the flame blow-off limits through augmentation. The experimental apparatus employed here comprises a fuel nozzle placed at the center of a concentric annulus with an outer cylinder encompassing the nozzle. The fuel jet is allowed to eject upwards and turbulent jet diffusion flames are formed by igniting the jet, then by increasing the volume flow rate of the fuel. The annular counterflow technique was employed to augment the turbulent shear effect. It is found that (1) the augmentation of turbulent shear effect exerted on the shear layer formed between the jet flames and the opposed flow of air causes an increase in temperature of the cold fuel gas at the flame center and an extension of flame blowoff limits; (2) flame lift-off heights are suppressed; (3) the lift-off propensity of the diffusion flame is alleviated by such augmentation.

Flame Blowoff Limit Phenomenon of Turbulent Jet Diffusion Flames With Annular Counterflow

2002 ◽  
Author(s):  
Shuichi Torii ◽  
Sze Man Simon Chan ◽  
Toshiaki Yano
Keyword(s):  
Diffusion Flames ◽  
Outer Cylinder ◽  
Turbulent Jet ◽  
Turbulent Shear ◽  
Jet Diffusion Flames ◽  
Opposed Flow ◽  
Fuel Jet ◽  
Experimental Apparatus ◽  
Normal Diffusion ◽  
Lift Off

The present study deals with the transport phenomena of turbulent jet diffusion flames with air-suction flow and the possibility of extending the flame blow-off limits through the shear stress augmentation using the annular counterflow technique. The experimental apparatus employed here comprises a fuel nozzle placed at the center of a concentric annulus with an outer cylinder adopted to encompass the nozzle. Fuel jet is allowed to eject upwards and turbulent jet diffusion flames are formed by igniting the jet and by increasing the volume flow rates of fuel. It is found that (1) the augmentation of turbulent shear effect exerted on the shear layer formed between the jet flames and the opposed flow of air causes an extension of flame blowoff limits, (2) by using the annular counterflow technique, the flame lift-off height is suppressed than the normal diffusion flame, and (3) its height is correlated using the effective air-suction momentum flux proposed here.

The blowout mechanism of turbulent jet diffusion flames

2006 ◽  
Vol 145 (3) ◽  
pp. 481-494 ◽  
Author(s):  
Chih-Yung Wu ◽  
Yei-Chin Chao ◽  
Tsarng-Sheng Cheng ◽  
Yueh-Heng Li ◽  
Kuo-Yuan Lee ◽  
...  
Keyword(s):  
Diffusion Flames ◽  
Turbulent Jet ◽  
Jet Diffusion Flames
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